How to use Text Cipher Tool
- Enter a short message and choose the cipher.
- For Caesar enter the shift; for Vigenere enter an ASCII-letter key.
- Encode or decode, then compare the letters with your original.
Example: Text Cipher Tool
Text Cipher Tool: ROT13 forward transformation complete. This is educational and does not protect secrets.
Options
- Cipher choice
- ROT13 uses a fixed rotation. Caesar uses the entered shift, while Vigenere uses a bounded ASCII-letter key.
- Direction
- Forward and reverse apply the selected transformation. ASCII letter case remains; punctuation and other scripts are preserved.
Supported inputs and limits
Where your input is processed
This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.
Classical ciphers belong to puzzles and learning
These transformations are easy to analyze and do not provide modern secrecy or authentication. A long key or unfamiliar-looking result does not make this page suitable for passwords or private messages. Use it to study letter mappings and verify a round trip on text you can safely expose.
Questions about Text Cipher Tool
Is ROT13 reversible?
Yes. Applying ROT13 again returns the same ASCII letters you started with because the alphabet rotation is half a turn.
Do spaces use up Vigenere key letters?
The key advances when a supported ASCII letter is transformed. Other characters remain unchanged without advancing it.
Can I protect a password with this?
No. Classical substitution ciphers are easily reversed or analysed and should not be used to protect secrets.